Cutting tool holder

ABSTRACT

A holder body 10 has an extension 11 whose upper surface is provided with a V-shaped groove 12 which accommodates a cutting bit insert 15 and a clamp member 18, both having complimentary V-shaped bottoms. The rear edge of the insert abuts a stop pin 19 and the nose 20 of the clamp member bears against a recess 17 in the insert. The clamp member is secured to the body by a double threaded screw 22.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a cutting tool holder comprising a holderbody, a cutting bit insert and a clamping device.

2. Description of the Prior Art

Holders with a short V-shaped seat for the cutting bit insert, which isformed with a corresponding bottom-surface, have previously beenmanufactured. The seat terminates at a transverse rear shoulder whichthe insert abuts. From this shoulder one part extends backwards to theholder body, which part is intended to support the clamping means andhas a plane bottom surface. The manufacture of such a holder involvesgreat problems since the V-shaped slot is shaped by a circular millwhose cutting surface, without contacting the shoulder, must cut awayall of the material up to the shoulder. With these holders there is alsoa risk that the clamping means may move sideways and in time loosen itsgrasp on the insert. These holders also have an opening between the rearend of the clamping device and the holder body which results in abrasivedirt and chips accumulating in the tool.

SUMMARY OF THE INVENTION

These drawbacks are eliminated by this invention whereby a rigid andreliable clamping of the cutting bit insert is achieved while at thesame time the manufacture of the holder body and the clamping means hasbeen simplified.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows a vertical section through a holder according to theinvention,

FIG. 2 shows a horizontal plan view of the holder,

FIG. 3 shows a section along the line III--III in FIG. 1,

FIG. 4 shows a section along the line IV--IV in FIG. 1, and FIGS. 5 and6 show other embodiments of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIGS. 1 and 2 the holder comprises a holder body 10 with anextending narrow part 11. The upper surface of the narrow part is shapedas a seat 12 having a V-shaped groove which in the front part of theseat is horizontal but at the rear end via a curved part 13 ends in theupper horizontal surface 14 of the holder body. The front part of theseat receives a cutting bit insert 15 which is correspondingly shapedwith a profiled bottom surface 16 to lie firm against the surfaces ofthe groove, and with a recess 17 which is abutted by a clamping means18. The movement of the insert in the backwards direction is limited bya pin 19 inserted into a bore in the groove. The clamping means is inits front part formed with a nose 20 which rests in the recess 17 whilethe bottom surface has a shape which corresponds to the rear part of thegroove, whereby the clamping means in its rear part is rounded and hasan acute profile when seen in section.

Near the middle of the clamping means is a threaded bore 21, a doublethreaded screw 22, and a threaded bore 23 in the groove, by which theclamping means is secured to the holder body. The double threaded screwhas an upper part which is right-hand threaded and a lower part which isleft-hand threaded, resulting in that the clamping means can be rapidlyfastened and loosened to change the insert. The clamping means has inits front part below the nose 20 a vertical slot 24 (FIG. 3) wherein thepin 19 lies when the clamping means is fastened. The pin thus serves asa steering means for the vertical movement of the clamping means whenchanging the insert.

This arrangement provides for the safe and simple fastening of theinsert, and it is simple to manufacture since the V-shaped groove can beeasily cut out with a circular mill whereby this groove serves as acentering means for both the insert and the clamping means.

The embodiment shown in FIG. 5 comprises a holder body 24 with anextending narrow part 25 supporting an insert 26 and a clamping means27. The longitudinal direction of the extending part is perpendicular tothe longitudinal direction of the holder body whereby the tool can beused to make holes in workpieces.

The embodiment shown in FIG. 6 comprises a holder body 28 having aninsert 29 and clamping means 30. The width of the holder body is of thesame size as the insert. The holder body can be moved in itslongitudinal direction in a support device 31 and has a lower surface 32and an upper surface 33 both having V-shaped grooves. The holder bodycan be clamped to the support device 31 by sliding means 34 with a shapecorresponding to the upper surface 33 of the holder body by means ofscrews 35. By this arrangement different types of workpieces can becut-off with the same tool.

It is also possible to avoid using a pin to take up the forcestransferred to the insert. Instead, the clamping means can serve thesame purpose. Also, the axes of the bores 21 and 23 need not beperpendicular to the surface of the seat but can be angled or offset sothat the rear part of the clamping means will abut the seat before thenose abuts the insert thus ensuring that there will be no risk ofsideways movements of the clamping means during the last portion of thefastening movement.

What is claimed is:
 1. A cutting tool holder including a holder body, achangeable cutting bit insert and a clamping means, the holder bodyhaving a generally horizontal, slender, section-profiled seat whoseupper surface is below the upper surface of the holder body and intendedto support the insert in its front part while the rear part supports theclamping means, characterized by: the part (13) connecting said uppersurface of the seat with the upper surface (14) of the holder bodyhaving the same profiled shape as the horizontal part of the seat, andthe clamping means having a shape corresponding to the seat and theconnecting part.
 2. A cutting tool holder according to claim 1characterized in that the seat and the connecting part have a V-shapedprofile, and the connecting part is a curved surface.
 3. A cutting toolholder according to claim 1 characterized by the seat having anextending pin (19) placed behind the insert and intended to serve as astop member for the insert.
 4. A cutting tool holder according to claim1 characterized in that the clamping means is fastened to the seat by adouble-threaded screw.
 5. A cutting tool holder according to claim 1characterized in that the clamping means has a nose (20) in its frontpart adopted to rest in a recess (17) in the insert.
 6. A cutting toolholder according to claim 3 characterized in that the bottom surface ofthe clamping means has a recess (24) receiving the pin, whereby the pinserves as an aligning device for the clamping means when fastened.
 7. Acutting tool holder according to claim 1 characterized in that thelongitudinal direction of the seat is perpendicular to the longitudinaldirection of the holder body.
 8. A cutting tool holder according toclaim 1 characterized in that the holder body has substantially the samewidth as the insert and can be clamped in different extending positionsin a support device.